Road-side network node and method to operate the road-side network node

ABSTRACT

A method to operate a road-side network node in a cell-supported radio communications network and in an adhoc radio communications network is provided. The method includes providing data to be transmitted; and determining a transmission instruction for the data, the transmission instruction including a channel selection indicating a) a transmission of the data via a sidelink radio channel of the cell-supported radio communications network, b) a transmission of the data via an adhoc radio channel of the adhoc radio communications network, or c) a transmission of the data via the sidelink radio channel and the adhoc radio channel. The method also includes initiating a transmission of the data via the sidelink radio channel and/or via the adhoc radio channel according to the transmission instruction.

FIELD

The present invention is directed to a road-side network node and methodto operate the road-side network node.

BACKGROUND INFORMATION

State-of-the-art vehicles are able to exchange information with othervehicles in their vicinity (V2V: Vehicle to Vehicle). Also, vehicleswith roadside infrastructure can communicate wirelessly (V2I: Vehicle toInfrastructure). Likewise, the vehicle can communicate wirelessly with abackend server in the Internet (V2N: Vehicle to Network) or with apedestrian terminal (V2P: Vehicle to Person). Overall, thiscommunication is referred to as Vehicle-to-Everything (V2X).

The development of new functions and services in the automotive industrysuch as automated driving benefits from V2X. Road safety, ride comfortand energy and traffic efficiency can be improved. This leads to newproducts and business models for automakers, automotive suppliers andother service providers.

The first generation of V2X applications to be deployed in the comingyears is primarily related to road application. Their goal is to providethe driver with information about the road environment. Vehiclesperiodically provide status information (e.g., position, speed,acceleration, etc.) and/or event information (rescue mission, vehiclestagnant, traffic jam). This information is usually issued locally inthe form of text messages. From neighboring vehicles, this event-basedinformation can be sent to a central network unit (base station,backend).

SUMMARY

In accordance with the present invention, a road-side network node and amethod to operate the road-side network node, are provided.

According to a first aspect of the present invention, a road-sidenetwork node is provided. The road-side network node comprising aprocessor, a memory, a first radio module for operating in acell-supported radio communications network, a second radio module foroperating in an adhoc radio communications network, and at least oneantenna. The road-side network node is configured to: provide data to betransmitted; determine a transmission instruction for the data, thetransmission instruction comprising a channel selection indicating a) atransmission of the data via a sidelink radio channel of thecell-supported radio communications network, b) a transmission of thedata via an adhoc radio channel of the adhoc radio communicationsnetwork, or c) a transmission of the data via the sidelink radio channeland the adhoc radio channel; and initiate a transmission of the data viathe sidelink radio channel and/or via the adhoc radio channel accordingto the transmission instruction.

Advantageously, the channel selection is determined dynamically.

According to an advantageous embodiment, the road-side network node isconfigured to determine a first Service quality of the sidelink radiochannel; determine a second Service quality of the adhoc radio channel;determine the channel selection in dependence on the first and secondService quality.

Advantageously the channel selection in dependence on the lowercongestion makes it possible to shape the traffic in both radionetworks. In particular, the radio channels get load balanced whenmessages are injected preferably into the channel with the lowercongestion value.

According to an advantageous embodiment of the present invention, theroad-side network node is configured to determine or provide a targetpropagation range for the data; determine a first propagation range viathe sidelink radio channel; determine a second propagation range via theadhoc radio channel; determine the channel selection to a) or b) independence on the target propagation range and in dependence on thefirst and second message propagation range.

In dependence on the desired propagation range the appropriate radiochannel is selected. This helps to reduce interference as messageswithout an additional benefit are avoided to fill the sidelink and adhocradio channel.

According to an advantageous embodiment of the present invention, theroad-side network node is configured to determine a high congestion ofone of the sidelink radio channel and the adhoc radio channel; overridethe determination of the channel selection in dependence on the targetpropagation if the high congestion is determined.

When a propagation range of one radio channel fits better the targetpropagation range but this radio channel is congested, the lesscongested radio channel will be used.

According to an advantageous embodiment the road-side network node isconfigured to determine a first repetition rate of the transmissioninstruction in dependence on the first and second Service quality;determine a second repetition rate of the transmission instruction independence on the first and second Service quality;

-   -   reiteratively initiate the transmission of the data via the        sidelink radio channel according to the first repetition rate;        and reiteratively initiate the transmission of the data via the        adhoc radio channel according to the second repetition rate.

By adapting the repetition rate in dependence on the Service qualitysituation on the sidelink and adhoc radio channels, the radio resourcesare better utilized and interference and high congestion situations onthe radio channels are avoided. In case of emergency messages thedesired Service quality can be set high in order to penetrate both radionetworks with a higher repetition rate.

According to an advantageous embodiment of the present invention, theroad-side network node is configured to determine the radio channel witha higher congestion value in dependence on the first and second Servicequality; decrease the repetition rate for the radio channel with thehigher congestion value.

Load reduction on the channel with the higher congestion value isachieved. Especially, if a majority of participating network nodesreduces the repetition rate, the channel load can be effectivelyreduced.

According to an advantageous embodiment the road-side network node isconfigured to determine the transmission instruction to alternate atransmission initiation on the sidelink radio channel and the adhocradio channel.

Advantageously both radio channels are used in an interleaved manner tospread the data in both networks. This increases the probability of anetwork node in the vicinity of the transmitting network node willreceive the data.

According to an advantageous embodiment of the present invention, theroad-side network node is configured to determine the first repetitionrate for the sidelink channel and the second repetition rate for thesidelink channel in dependence on a target repetition rate.

Message propagation is divided between the radio channels while a targetrepetition rate can be maintained.

According to an advantageous embodiment the road-side network node isconfigured to determine a third repetition rate of at least one furtherroad-side network node of the cell-supported radio communicationsnetwork; and determine the first repetition rate in dependence on thethird repetition rate.

The adaption of the first repetition rate in dependence on the measuredrepetition rate on the sidelink allows to reduce the transmissions whenthere are few vehicles in the vicinity of the road-side network node. Onthe other hand, the repetition rate is increased if there are manyvehicles in the vicinity of the road-side network node.

According to an advantageous embodiment of the present invention, theroad-side network node is configured to determine a fourth repetitionrate of at least one even further road-side network node of the adhocradio communications network; and determine the second repetition ratein dependence on the fourth repetition rate.

The adaption of the second repetition rate in dependence on the measuredrepetition rate on the adhoc radio channel allows to reduce thetransmissions when there are few vehicles in the vicinity of theroad-side network node transmitting on the adhoc radio channel. On theother hand, the second repetition rate is increased if there are manyvehicles in the vicinity of the road-side network node.

According to an advantageous embodiment of the present invention, theroad-side network node is configured to determine a similarity value independence on a first data entity to be transmitted and second dataentity, which has been transmitted; initiate a transmission of the firstdata entity if the similarity value exceeds a threshold.

When there are no significant changes, the similarity value will notexceed the threshold and the transmission of the first data will notoccur. Keeping a minimum repetition rate ensures that newly arrivingvehicles in the vicinity will be informed with a reasonable delay.

According to an advantageous embodiment of the present invention, theroad-side network node is configured to receive data via the sidelinkchannel and/or the adhoc channel; determine a danger level in dependenceon received data; determine a minimum repetition rate for at least oneof the sidelink radio channel and the adhoc radio channel in dependenceon the danger level; and maintain the repetition rate for at least oneof the sidelink radio channel and the adhoc radio channel at or abovethe minimum repetition rate.

Severity situations can be detected by observing the danger level. Thismakes it possible for each vehicle to take timely measures to prevent anaccident or to mitigate the consequences.

According to an advantageous embodiment of the present invention, thereceived data comprises a current speed and/or a current location of adistant vehicle, and the road-side network node is configured todetermine the danger level in dependence on the current speed andcurrent location.

According to an advantageous embodiment of the present invention, theroad-side network node is configured to provide a transmissioninstruction request by a facility layer function or an application layerfunction; and determine the transmission instruction solely independence on the transmission instruction request, if the transmissioninstruction request is provided. Advantageously further dependencies ofthe transmission instruction are overridden.

According to a further aspect of the present invention, a method tooperate a road-side network node in a cell-supported radiocommunications network and in an adhoc radio communications network isprovided. The method comprises: providing data to be transmitted;determining a transmission instruction for the data, the transmissioninstruction comprising a channel selection indicating a) a transmissionof the data via a sidelink radio channel of the cell-supported radiocommunications network, b) a transmission of the data via an adhoc radiochannel of the adhoc radio communications network, or c) a transmissionof the data via the sidelink radio channel and the adhoc radio channel;and initiating a transmission of the data via the sidelink radio channeland/or via the adhoc radio channel according to the transmissioninstruction.

Further features and advantages are described herein in connection withexample embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a schematic perspective view of an exemplary trafficsituation.

FIG. 2a depicts schematically a layer structure.

FIG. 2b depicts schematically a flow chart.

FIG. 3 depicts schematically a flow chart.

FIG. 4 depicts schematically a data structure.

FIG. 5 depicts schematically a transmission coordination function.

FIG. 6 depicts schematically a flow chart.

FIG. 7 depicts schematically a flow chart.

FIG. 8 depicts schematically a flow chart.

FIG. 9 depicts schematically a reception coordination function.

FIG. 10 depicts schematically a determination of a similarity value.

FIG. 11 depicts schematically a flow chart.

FIG. 12 depicts schematically a flow chart.

FIG. 13 depicts schematically two interacting road-side network nodes.

FIG. 14 depicts schematically two interacting road-side network nodes.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 depicts a schematic perspective view of an exemplary trafficsituation around a traffic lights crossing 2. Each vehicle V1, V3comprises a network node NN1, NN3 forming an adhoc radio communicationsnetwork VANET. Each vehicle V2, V4 comprises a network node NN2, NN4,which form a cell-supported radio communications network CNET. A vehicleV5 and a traffic light TL comprise a network node NN5, NN6, which areconfigured to participate in the adhoc radio communications networkVANET and the cell-supported radio communications network CNET. Ofcourse also other fixed infrastructure entities besides traffic lightsmay comprise a network node like NN1, NN2, or NN6.

Each one of network nodes NN1, NN2, NN3, NN4, NN5, NN6, and NN7comprises a data bus B1, B2, B3, B4, B5, B6, and B7 interconnecting atleast a processor P1, P2, P3, P4, P5, P6, and P7, a memory M1, M2, M3,M4, M5, M6, and M7, and a satellite receiver G1, G2, G3, G4, G5, G6, andG7. The network nodes NN1, NN2, NN3, NN4, NN5, NN6 are road-side networknodes, which means that these network nodes are installed in a vehicleor a road infrastructure. The network node NN7 is a networkinfrastructure node, which means that this node is configured to managenetwork functions. The satellite receiver G1, G2, G3, G4, G5, G6, and G7is configured to receive at least one satellite Signal TS, for example aGPS, Global Positioning System, signal, originating from an earthsatellite S. On each of the memory M1, M2, M3, M4, M5, M6, and M7 acomputer program is stored, which implements the methods disclosed inthis description when executed on the corresponding processor P1, P2,P3, P4, P5, P6, and P7. Alternatively or additionally, the processorsP1, P2, P3, P4, P5, P6, and P7 are implemented as ASIC. Each one of thenetwork nodes NN1, NN3 comprises a radio module C1, C3 configured forthe transmission and reception of radio signals according to the adhocradio communications network VANET. Each one of the radio modules C1, C3is connected to an antenna A1, A3. Each one of the network nodes NN2,NN4 comprises a radio module D2, D4 configured for the transmission andreception of radio signals according to the cell-supported radiocommunications network CNET. Each one of the radio modules D2, D4 isconnected to an antenna A2, A4. Each one of the network nodes NN5, NN6comprises a radio module D5, D6 configured for the transmission andreception of radio signals according to the cell-supported radiocommunications network CNET, and a radio module C5, C5 configured forthe transmission and reception of radio signals according to the adhocradio communications network VANET. Each one of the radio modules D5, D6is connected to an antenna A5 d, A6 d. Each one of the radio modules C5,C6 is connected to an antenna A5 c, A6 c.

National authorities such as the “Bundesnetzagentur” of the FederalRepublic of Germany draw up a frequency usage plan which, for example,includes licenses for the different network operators. The networkoperator is allowed, under the assigned license, to connect the networkinfrastructure nodes and network nodes in an assigned licensed frequencyrange or frequency spectrum. In contrast, there are frequency ranges orfrequency spectra which are not assigned to any network operator and canbe freely used under certain boundary conditions such as, for example,dedicated transmission/reception power.

The network VANET provides an adhoc radio channel AHCH. The network CNETprovides the sidelink radio channel SLCH. Each one of the sidelink radiochannel SLCH and the adhoc radio channel AHCH is an instance of wirelessmedium, WM, use for the purpose of passing physical layer, PHY, protocoldata units, PDUs, between two or more network nodes. In both networksVANET and CNET radio signals are transmitted using the same oroverlapping unlicensed frequency range uFR. Uncoordinated use of thechannels SLCH and AHCH would lead to a deterioration of at least one ofboth channels SLCH and AHCH.

The network infrastructure node NN7 comprises a network interface 17 foraccessing other network nodes for example of a backhaul network. Thenetwork infrastructure node NN7 can also be designated as a base stationor eNodeB. The network infrastructure node NN7 is connected to astationary antenna A7 to send data on a downlink channel DC and toreceive data on an uplink channel UC. The antenna A7 comprises, forexample, a number of antennas and is designed, for example, as a remoteradio head, RRH. Of course, the network infrastructure node NN7 can berealized in a distributed manner, for example in the context of avirtualization, and may consist of a plurality of separated networknodes. The network infrastructure node NN7 and the roadside networknodes NN2, NN4, NN5 and NN6 are configured according to the LTE-V2Xstandard, for example.

The network infrastructure node NN7 and the antenna A7 provide a radioCL within which the roadside network nodes NN5 and NN4 are in-coverageand are able to communicate with the network infrastructure node NN7. Onthe other hand, the network nodes NN2 and NN5 do not reside within theradio CL, are out-of-coverage with regard to the network infrastructurenode NN7 and are not able to communicate directly with the networkinfrastructure node NN7.

The sidelink radio channel SLCH and a sidelink in general are defined,for example, by document 3GPP TS 36.300 V14.2.0 (2017-03), which isincorporated herein by reference. The network nodes NN2, NN4, NN5 andNN6 are configured according to 3GPP TS 36.300 V14.2.0 (2017-03). Thesidelink includes sidelink discovery, and V2X sidelink communication.The sidelink uses uplink resources and a physical channel structuresimilar to the uplink. The sidelink thus differs from the uplink withrespect to the physical channel.

The sidelink is limited to individual cluster transmission for thesidelink physical channels. Furthermore, the sidelink uses a 1-symbolgap at the end of each sidelink subframe. For V2X sidelinkcommunication, PSCCH, Physical Sidelink Control Channel, and PSSCH,Physical Sidelink Shared Channel, are transmitted in the same subframe.

Physical layer processing of transport channels in the sidelink differsfrom uplink transmission in the following steps: Scrambling: For PSDCH,Physical Sidelink Discovery Channel, and PSCCH, scrambling is notspecific to the network entity; Modulation: 64 QAM and 256 QAM are notsupported for the Sidelink (QAM: Quadrature amplitude modulation). ThePSCCH indicates sidelink resources and other transmission parametersused by the respective network node for the PSSCH.

For PSDCH, PSCCH and PSSCH demodulation, reference signals similar tothe uplink demodulation reference signals in the 4th symbol of the slotare transmitted in the normal CP, Cyclic Prefix, and in the third symbolof the slot in the extended CP. The sidelink demodulation referencesignal sequence length corresponds to the size (number of subcarriers)of the associated resource. For V2X Sidelink communication, referencesignals are transmitted in the 3rd and 6th symbols of the first slot andin the 2nd and 5th symbols of the second slot in the CP. For PSDCH andPSCCH, reference signals are generated based on a fixed base sequence,cyclic shift and orthogonal cover code. For V2X sidelink communication,the cyclic shift for PSCCH is randomly selected on each transmission.

For measurements of the sidelink radio channel, the following optionsare available on the side of the network nodes: Receiving power of thesidelink reference signal (S-RSRP); Receive power of the sidelinkdiscovery reference signal (SD-RSRP); Received power of the PSSCHreference signal (PSSCH-RSRP); Signal strength indicator for idelinkreference Signals (S-RSSI).

A sidelink resource pool can be provided pre-configured, semi-static, ordynamically and corresponds to a set of radio resources capable ofperforming a sidelink transmission via the sidelink radio channel SLCH.A network node performing sidelink communication in a mode 2 (uncoveredcase) autonomously selects a resource from a resource pool range, whichis configured by the network infrastructure node NN7 or a headend of asidelink duster in advance. A network node performing sidelinkcommunication in a mode 1 (covered case) selects a resource which hasbeen scheduled by the network infrastructure node NN7.

Each one of network nodes NN1, NN3, NN5, NN6 is configured, for example,according to the IEEE 802.11p Standard, especially IEEE 802.11p-2010dated Jul. 15, 2010 which is incorporated herein by reference. The IEEE802.11p PHY and MAC provide services for upper layer protocols forDedicated Short-Range Communications, DSRC, in the US and forCooperative ITS, C-ITS, in Europe. The network nodes NN1, NN3, NN5, NN6communicate directly with each other via an adhoc radio channel AHCH inthe unlicensed frequency range. The adhoc radio channel AHCH isarbitrated via a CSMA/CA (Carrier Sense Multiple Access/CollisionAvoidance) protocol by radio modules C1, C3, C5, C6.

The network node NN1 is configured to transmit data via the adhoc radiochannel AHCH and the network node NN3 can receive the data. All networknodes in the reception range of the radio signal as for example thenetwork node NN3 are able to receive such data. The adhoc radio channelAHCH and an adhoc radio channel in general and the ad hoc wirelesscommunication network VANET are described, for example, by the IEEEStandard “802.11p-2010—IEEE Standard for Information Technology—Localand Metropolitan Area Networks—” Specific Part 11: Wireless LAN MediumAccess Control (MAC) and Physical Layer (PHY) Specifications Amendment6: Wireless Access in Vehicular Environments, which is incorporatedherein by reference. IEEE 802.11p is a Standard for extending the WLANStandard IEEE 802.11. The goal of IEEE 802.11p is to establish wirelesstechnology in passenger vehicles and to provide a reliable interface forIntelligent Transport Systems (ITS) applications. IEEE 802.11p is alsothe basis for Dedicated Short Range Communication (DSRC) in the 5.85 to5.925 GHz band. To avoid confusion with the European DSRC version, theterm ITS-G5 is used rather than DSRC, especially in Europe.

To access the adhoc radio channel AHCH the network node NN1, NN3, NN5and NN6 use an enhanced distributed channel access, EDCA, and alisten-before-talk, LBT, procedure. The LBT comprises a backoffprocedure prior to transmitting on the adhoc radio channel AHCH. Firstthe network node NN1, NN3, NN5 or NN6 listens and waits until the adhocradio channel AHCH is available during a period of time, the period oftime AIFS being termed as arbitration inter-frame space AIFS. The adhocradio channel AHCH is sensed idle if a power level is lower than a firstthreshold value like 62 dBm and no adhoc preamble with a power levelhigher than a second threshold value like −82 dBm is determined. Theadhoc radio channel is busy if the channel is not sensed idle.

If the adhoc radio channel AHCH is sensed idle during the period of timeAIFS, the backoff procedure starts. A backoff timer is initialized as arandom number being multiples of a 9 μs slot time. The random number isdetermined within a contention window. The random backoff timer isdecreased by one when the adhoc radio channel AHCH is sensed idle. Foreach slot time the adhoc radio channel AHCH is sensed busy the randombackoff timer remains with the same value as before.

The network node NN1, NN3, NN5 or NN6 obtains a transmission opportunityTXOP if the backoff timer expires. If the network node NN1, NN3, NN5 orNN6 senses the adhoc radio channel as idle, it will transmit the data,if a transmission opportunity TXOP duration has not expired.

The receiving network node among the network nodes NN1, NN3, NN5, andNN6 will send an acknowledgement to the sending node upon reception ofthe data if the data was not transmitted in a broadcast mode.

The document “ETSI EN 302 663 V1.2.0 (2012-11)”, which is incorporatedherein by reference, describes both lowermost layers of ITS-G5technology (ITS G5: Intelligent Transport Systems operating in the 5 GHzfrequency band), the physical layer and the data link layer. The radiomodules C1, C3, C5, and C6 realize, for example, these two lowest layersand corresponding functions according to “ETSI TS 102 687 V1.1.1(2011-07)” in order to use the adhoc radio channel. The followingunlicensed frequency bands are available in Europe for the use of theadhoc radio channel AHCH, which are part of the unlicensed frequencyband NLFB: 1) ITS-G5A for safety-relevant applications in the frequencyrange 5.875 GHz to 5.905 GHz; 2) ITS-G5B for non-safety relatedapplications in the frequency range 5,855 GHz to 5,875 GHz; and 3)ITS-G5D for the operation of ITS applications in the 5.055 GHz to 5.925GHz frequency range. ITS-G5 allows communication between the two networkunits UE1 and UE2 out of the context of a base station. The ITS-G5enables the immediate exchange of data frames and avoids the managementoverhead that is used when setting up a network.

The document “ETSI TS 102 687 V1.1.1 (2011-07)”, which is incorporatedherein by reference, describes for ITS-G5 a “Decentralized CongestionControl Mechanism”. Among other things, the adhoc radio channel AHCHserves to exchange traffic safety and traffic efficiency data. The radiomodules C1, C3, C5, and C6 realize, for example, the functions asdescribed in the document “ETSI TS 102 687 V1.1.1 (2011-07)”. Theapplications and Services in the ITS-G5 are based on the cooperativebehavior of the roadside network nodes that make up the adhoc networkVANET (VANET: vehicular ad hoc network). The adhoc network VANET enablestime-critical road traffic applications that require rapid Informationexchange to alert and assist the driver and/or vehicle in good time. Toensure proper functioning of the adhoc network VANET, “DecentralizedCongestion Control Mechanisms” (DCC) is used for the adhoc radio channelAHCH of ITS-G5. DCC has features that reside on multiple layers of theITS architecture. The DCC mechanisms are based on knowledge about thechannel. The channel state Information is obtained by channel probing.Channel state information can be obtained by the methods TPC (transmitpower control), TRC (transmit rate control) and TDC (transmit dataratecontrol). The methods determine the channel state information inresponse to received signal level thresholds or preamble informationfrom detected packets.

The adhoc radio communications network VANET and the cell-supportedradio communications network CNET differ in various aspects-Differencesbetween both technologies are already present in the coding/decodingchain, therefore in modulation and coding schemes. This does not allow asuccessful decoding of a received signal of the other technology.Different reference symbols are used in a different way: sidelinkreference symbols are transmitted at certain radio resources during atransmission via the sidelink radio channel SLCH. On the other hand,adhoc reference symbols are transmitted at the beginning of atransmission via the adhoc radio channel AHCH. Moreover, thetransmission via the sidelink radio channel SLCH requires that theparticipating network nodes are synchronized in time in order tocorrectly decode the received signal. The adhoc radio channel on theother hand allows connectionless, unsynchronized transmission ofsignals.

In the shown traffic situation the network nodes NN1 to NN6 are locatedsuch, that the radio power of each network nodes NN1 to NN6 issufficient to reach another one of the network nodes NN1 to NN6. Thus,transmissions on the channels AHCH and SLCH which overlap in frequencycan adversely affect each other. One aim of this description is toreduce this disadvantageous mutual influence.

For example, the vehicle V5 is an emergency vehicle in emergencyoperation and communicates its emergency status in a message M5T via theadhoc radio channel ADCH and the sidelink radio channel to the trafficlight TL. The network node NN5 is configured to transmit a message viathe sidelink radio channel SLCH and/or via the adhoc radio channel AHCH,which can be received by the network node NN6. As both network nodes NN5and NN6 comprise the radio modules C5, D5, C6, D6 for both networks CNETand VANT, the access to both technologies is possible. The network nodesNN5 and NN6 can also be termed gateway nodes. The sidelink radio channelSLCH between the network nodes NN5 and NN6 is operated in thedistributed mode.

In dependence of the received message the traffic light TL closes thecrossing for cross traffic. Upon switching to red, the traffic lightcommunicates its red-light status in a message MT1 via the adhoc radiochannel AHCH to the vehicle V1 in order to reduce its speed. The vehicleV1 moves with a speed of 100 km/h and communicates the speed in amessage M13 via the adhoc radio channel ADCH to the other vehicle, e.g.,vehicle V3.

The network node NN2 is configured to transmit a message M2T via thesidelink radio channel SLCH to the network node NN6. As both networknodes NN2 and NN6 reside outside the radio cell CL, the access to thesidelink radio channel SLCH is not controlled by a networkinfrastructure node. The sidelink radio channel SLCH between the networknodes NN2 and NN6 is operated in the distributed mode.

The network node NN4 is configured to transmit a message M45 via thesidelink radio channel SLCH to the network node NN5. As both networknodes NN4 and NN5 reside in the radio cell CL, the access to thesidelink radio channel is controlled by the network infrastructure nodeNN7. The sidelink radio channel SLCH between the network nodes NN4 andNN5 is operated in mode 1 or managed mode, which means that the networkinfrastructure node NN7 Controls the transmission on the sidelink radiochannel SLCH via corresponding scheduling assignments SA in the downlinkchannel DC. The network infrastructure node NN7 comprises a schedulerwhich determines the scheduling assignments SA for the sidelink radiochannel SLCH. The scheduling assignments SA are control signalstransmitted via the downlink channel DC and indicate which sidelinkradio resource are to be used by the network nodes NN4, NN5 to transmitthe data via the sidelink. The scheduling assignments SA are determinedin such a way that collisions are avoided and interference is minimized.This is of great importance under high network load, as the schedulerentity is able to guarantee a Quality-of-Service (QoS), e.g., data rate,data reliability, packet error ratio, or delay, to differentapplications by allocating sidelink radio resources to each network nodeNN4, NN5 based on the Service quality requirements of the application.The data transmissions associated with the scheduling assignments SA canoccupy adjacent resource blocks RB in the same sub-frame or non-adjacentRBs depending on the latency required by the application. The schedulingand the control by the network infrastructure node NN7 can only beperformed in areas where the signals of the node NN7 are available(in-coverage). In this mode the scheduling and interference managementof radio traffic is assisted by the network infrastructure node NN7 viacontrol signaling over the downlink channel DC. The networkinfrastructure node NN7 assigns for each network node the resources (ea.time and frequency ranges) to be used for the sidelink in a dynamicmanner.

Since services should be available everywhere including areas where nonetwork coverage by a network infrastructure node NN7 is available,there is a further configuration or deployment mode for the sidelinkradio channel SLCH, namely the distributed mode. In the distributed modethe scheduling and interference management of radio traffic is supportedbased on distributed algorithms implemented between the network nodes,for example NN2 and NN5. These distributed algorithms are based onsensing with semi-persistent transmission based on the fact that theradio traffic generated by each network node NN2, NN5 is mostly periodicin nature. This technique enables sensing the occupation of a radioresource and estimate the future congestion on it. This optimizes theuse of the sidelink by enhancing resource separation betweentransmitters that are using overlapping resources. Additionally, amechanism where resource allocation is dependent on geographicalinformation is able to reduce the number of network nodes competing forthe same resources which reduces the collision probability. Thedistributed mode is mainly used in out-of-coverage scenarios anddesignated also as non-cell-supported mode. Consequently, thecell-supported communications network CNET provides the cell-supportedmode (in-coverage) and the distributed mode (out-of-coverage). Evenout-of-coverage the network CNET is termed cell-assisted radiocommunications network.

Both modes are defined to use a dedicated carrier for radiocommunications, meaning the spectrum band is only used for the directside-link based V2V Communications. The design is scalable for differentbandwidths (e.g., 10 MHz or multitudes of 10 MHz). For timesynchronization GNSS, Global Navigation Satellite System, is used inboth cases.

In this description, reference is made to a single uplink channel and asingle downlink channel. For example, the uplink channel and thedownlink channel include respective subchannels. Several channels can beused in the uplink as well as in the downlink. The same applies to thesidelink radio channel SLCH and the adhoc radio channel AHCH.

FIG. 2a shows schematically a layer structure for a gateway network nodesuch as the network nodes NN5 and NN6 of FIG. 1. The protocol stack ofthe gateway network node basically follows the ISO/OSI reference modeland comprises horizontal protocol layers and two vertical protocolentities. The horizontal protocol layers comprise: At least two accesstechnology layers ACC1 and ACC2 for the physical and data link layers,at least two network & transport layers N&T1 and N&T2, one coordinationlayer COORD, a facilities layer FAC, and an applications layer APP.Further network & transport layers comprise protocols for data deliveryto and from the gateway node to other network nodes, such as networknodes in the core network (e.g., the Internet)

The access technology layer ACC1 comprises an access scheme for the LTEphysical layer, based on Orthogonal Frequency Division Multiplexing(OFDM) with a cyclic prefix (CP) in the downlink, and on Single-CarrierFrequency Division Multiple Access (SC-FDMA) with a cyclic prefix in theuplink and sidelink. To support transmission in paired and unpairedspectrum, two duplex modes are supported: Frequency Division Duplex(FDD), supporting full duplex and half duplex operation, and TimeDivision Duplex (TDD). The physical layer specification of the accesstechnology layer ACC1 consists of the documents 3GPP TS 36.201, TS36.211, TS 36.212, TS 36.213, TS 36.214 and TS 36.216, which areincorporated herein by reference. The physical layer of the accesstechnology layer ACC1 is defined in a bandwidth agnostic way based onresource blocks, allowing the LTE Layer 1 to adapt to various spectrumallocations. A resource block spans either 12 sub-carriers with asub-carrier bandwidth of 15 kHz or 24 sub-carriers with a sub-carrierbandwidth of 7.5 kHz each over a slot duration of 0.5 ms, or 144sub-carriers with a sub-carrier bandwidth of 1.25 kHz over a slotduration of 1 ms. Narrowband operation is also defined, whereby certainUEs may operate using a maximum transmission and reception bandwidth of6 contiguous resource blocks within the total system bandwidth. ForNarrowband Internet of Things (NB-IoT) Operation, a network nodeoperates in the downlink using 12 sub-carriers with a sub-carrierbandwidth of 15 kHz, and in the uplink using a single sub-carrier with asub-carrier bandwidth of either 3.75 kHz or 15 kHz or alternatively 3, 6or 12 sub-carriers with a sub-carrier bandwidth of 15 kHz. NB-IoT doesnot support TDD Operation in this release. The radio frame structuretype 1 is only applicable to FDD (for both full duplex and half duplexoperation) and has a duration of 10 ms and consists of 20 slots with aslot duration of 0.5 ms. Two adjacent slots form one sub-frame of length1 ms, except when the subcarrier bandwidth is 1.25 kHz, in which caseone slot forms one sub-frame. The radio frame structure type 2 is onlyapplicable to TDD and consists of two half-frames with a duration of 5ms each and containing each either 10 slots of length 0.5 ms, or 8 slotsof length 0.5 ms and three special fields (DwPTS, GP and UpPTS) whichhave configurable individual lengths and a total length of 1 ms. Asubframe consists of two adjacent slots, except for subframes whichconsist of DwPTS, GP and UpPTS, namely subframe 1 and, in someconfigurations, subframe 6. Both 5 ms and 10 ms downlink-to-uplinkswitch-point periodicity are supported. Adaptation of theuplink-downlink subframe configuration via Layer 1 signaling issupported. Sidelink transmissions via the sidelink radio channel aredefined for ProSe, Proximity Services, Direct Discovery and ProSe DirectCommunication between network nodes. The sidelink transmissions use thesame frame structure as uplink and downlink when the network nodes arein network coverage; however, the sidelink transmissions are restrictedto a sub-set of the uplink resources. V2X communication between networknodes is supported via sidelink transmissions or via the networkinfrastructure node.

Layer 2 of the access technology layer ACC1 is split into the followingsublayers: Medium Access Control (MAC), Radio Link Control (RLC) andPacket Data Convergence Protocol (PDCP). The multiplexing of severallogical channels (i.e., radio bearers) on the same transport channel(i.e., transport block) is performed by the MAC sublayer. In both uplinkand downlink, when neither CA nor DC are configured, only one transportblock is generated per TTI in the absence of spatial multiplexing. InSidelink, only one transport block is generated per TTI. The layer 2specification of the access technology layer ACC1 consists of thedocument 3GPP TS 36.300 V14.2.0 (2017-03), which is incorporated hereinby reference.

The network and transport layer N&T 1 is used for the transmission andreception of messages. The network and transport layer N&T1 isconfigured according to the document 3GPP TS 23.285 V14.2.0 (2017-03),which is incorporated herein by reference. The message transmission andreception is done via unicast and/or via Multimedia Broadcast MulticastServices, MBMS. The V2X communication via unicast over the LTE-Uureference point supports roaming operations. The network and transportlayer N&T2 supports the transport of IP based messages over UDP/IPpackets. UDP is selected since it has shorter latency due to noconnection setup, and since IP multicast works with UDP only. Thenetwork node sends a V2X message over UDP/IP to a V2X Application Serveraddress. The V2X Application Server receives the V2X message in a UDP/IPpacket on a V2X Application Server address.

The access technology layer ACC2 provides access to the adhoc radiochannel according to IEEE Std 802.11p™-2010: Wireless Access inVehicular Environments (Amendment 6) and IEEE Std 802.11™-2016: Part 11:Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)Specifications.

The layer N&T2 is an ITS network & transport layer and comprisesprotocols for data delivery among network nodes of the adhoc radiocommunications network. ITS network protocols particularly include therouting of data from source to destination through intermediateadhoc-capable nodes and the efficient dissemination of data ingeographical areas. ITS transport protocols provide the end-to-enddelivery of data and, depending on requirements of ITS facilities andapplications, additional services, such as reliable data transfer, flowcontrol and congestion avoidance. A particular protocol in the ITSnetwork & transport layer is the Internet protocol IP Version 6 (IPv6).The usage of IPv6 includes the transmission of IPv6 packets over ITSnetwork protocols, dynamic selection of ITS access technologies andhandover between them, as well as interoperability issues of IPv6 andIPv4. The ITS network & transport layer comprises several network andtransport protocols. In detail the gateway network node can execute aGeoNetworking protocol, Transport protocols over GeoNetworking, such asthe Basic Transport Protocol and other GeoNetworking transportprotocols, Internet protocol IP Version 6 with IP mobility support andoptionally support for network mobility, Internet protocol IP Version 4for transition to IPv6, User Datagram Protocol UDP, Transmission ControlProtocols TCP, other network protocols such as SCTP.

The facilities layer FAC provides a collection of functions to supportapplications. The facilities provide data structures to store, aggregateand maintain data of different type and source (such as from vehiclesensors and from data received by means of communication). As forcommunication, facilities enable various types of addressing toapplications, provide message handling and support establishment andmaintenance of communication sessions. An important facility is themanagement of services, including discovery and download of services assoftware modules and their management in the network node. Furthermore,the facility layer FAC provides and manages local dynamic maps, whichindicate the position and status of vehicles in the vicinity.

The applications layer APP refers to applications and use cases for roadsafety, traffic efficiency, infotainment and business.

The management entity MAN is responsible for configuration of a networknode, cross-layer information exchange among the different layers andothers tasks. The security entity SEC provides security and privacyservices, including secure messages at different layers of thecommunication stack, management of identities and security credentials,and aspects for secure platforms (firewalls, security gateway,tamper-proof hardware).

The coordination layer COORD allows a coordination of both radiotechnologies provided. For example, for usage of the GeoNetworking overdifferent access technologies, the specification of the protocol issplit into a media-independent part, namely the coordination layer COORDand a media-dependent part, namely the access technology layer ACCT andthe network & transport layer N&T 1 on the one side and accesstechnology layer ACC2 and the network & transport layer N&T2 on theother side. GeoNetworking shall provide ad hoc networking based ongeographical addressing and geographical routing between network nodesusing short-range wireless technology. It shall allow the addressing ofroad-side network nodes based on their individual network addresses andalso facilitate the addressing of geographical areas. For routing,GeoNetworking shall support point-to-point and point-to-multipointcommunication, as well as the distribution of data packets ingeographical areas, i.e., to all nodes in a geographical area(GeoBroadcast) or to any node in a geographical area (GeoAnycast).

The coordination layer COORD is configured to: exchange data with atleast a second road-side network node via a sidelink radio channel ofthe cell-supported radio communications network; and exchange data withat least a third road-side network node via an adhoc radio channel ofthe adhoc radio communications network. The first access technologylayer ACC1 is used for said exchange of data with at least the secondroad-side network node. So, the exchange of data with the secondroad-side network node is operated according to at least one of 3GPP TS36.201, TS 36.211, TS 36.212, TS 36.213, TS 36.214 and TS 36.216. Thesecond access technology layer ACC2 is used for said exchange of datawith at least the third road-side network node. So, the exchange of datawith at least the third road-side network node is operated according toIEEE 802.11 p-2010 and/or ETSI EN 302 663 V1.2.0 (2012-11).

FIG. 2b depicts a flow chart for operating one of the network nodes NN5,NN6. Data is exchanged in a step 202 with at least a second road-sidenetwork node via a sidelink radio channel of the cell-supported radiocommunications network. Data is exchanged in a step 204 with at least athird road-side network node via an adhoc radio channel of the adhocradio communications network.

FIG. 3 depicts schematically a flow chart to operate a gateway networknode such as the road-side network nodes NN5 and NN6 of FIG. 1.According to a step 302 data to be transmitted is provided by an upperlayer, for example by an application function or by a facility function.According to a step 304 a transmission instruction for the data isdetermined. The transmission instruction comprises a channel selectionindicating a) a transmission of the data via the sidelink radio channelof the cell-supported radio communications network, b) a transmission ofthe data via the adhoc radio channel of the adhoc radio communicationsnetwork, or c) a transmission of the data via the sidelink radio channeland the adhoc radio channel. According to a step 306 a transmission ofthe data is initiated via the sidelink radio channel and/or via theadhoc radio channel according to the transmission instruction.Therefore, the gateway network node is configured to exchange data withat least a second road-side network node via a sidelink radio channel ofthe cell-supported radio communications network; and to exchange datawith at least a third road-side network node via an adhoc radio channelof the adhoc radio communications network. According to channelselections a) and b) only one of both channels is selected.

FIG. 4 depicts schematically a data structure 400. The data structure400 comprises a data entity DE with a destination address dest, data,which is transmitted via the sidelink radio channel and/or the adhocradio channel, and a lifespan LS of the data. The destination addressdest refers to a geographical area or a single network node. The datastructure 400 comprises a transmission instruction TI. The transmissioninstruction comprises a first repetition rate RR1 for initiatingtransmissions via the sidelink radio channel, a second repetition rateRR2 for initiating transmissions via the adhoc radio channel, a phasedifference dPH between the repetition rates RR1 and RR2, and the channelselection CS. The channel selection CS indicates a) the transmission ofthe data via the sidelink radio channel of the cell-supported radiocommunications network, b) the transmission of the data via the adhocradio channel of the adhoc radio communications network, or c) thetransmission of the data via the sidelink radio channel and the adhocradio channel. Depending on the data type a target repetition rate RR ispre-configured.

FIG. 5 depicts schematically a transmission coordination function. Dataentities DE1, DE2, and DE3 are provided by an application layer functionto a coordination block 500. For each access technology a servicequality is determined. The first service quality SQ1 of the sidelinkradio channel and the second service quality SQ2 of the adhoc radiochannel are determined and provided to the block 500. The block 500determines the channel selection CS to a), b) or c) in dependence on thefirst and second SQ1, SQ2. The service quality SQ1, SQ2 comprises atleast one of: packet loss, bit rate, throughput, transmission delay,availability, jitter, congestion level, or detected Quality of ServiceQoS.

For example, the block 500 determines the radio channel with a lowercongestion in dependence on the first and second SQ1, SQ2 and determinethe channel selection to a) or b) to transmit the data on the radiochannel with the lower congestion value. The first and second SQ1 SQ2are a) determined from channel measurements, b) derived from historicdata, or c) determined as a prediction.

In yet another example, the block 500 increases one of the repetitionrates RR1, RR2 for the radio channel with the lower congestion value. Inorder to accomplish this, the block 500 determines the first repetitionrate RR1 of the transmission instruction in dependence on the first andsecond SQ1, SQ2, determines the second repetition rate RR2 of thetransmission instruction in dependence on the first and second SQ1, SQ2.Then the block 500 reiteratively initiates the transmission of the dataof data entity DE1 via the sidelink radio channel according to the firstrepetition rate RR1, and reiteratively initiates the transmission of thedata of the data entity DE2 via the adhoc radio channel according to thesecond repetition rate RR2. If the first or second repetition rate RR1,RR2 is determined to zero, no transmission occurs via the sidelink oradhoc channel. For example, the block determines the radio channel witha higher congestion value in dependence on the first and second SQ1, SQ2by comparing both SQ1 and SQ2 and decrease the repetition rate RR1, RR2for the radio channel with the higher congestion value. Therefore, theblock 500 coordinates a use of the first access technology layer ACC1depending on a use of the second access technology layer ACC2. The block500 coordinates a use of the second access technology layer ACC2depending on a use of the first access technology layer ACC1. Insummary, the block 500 performs a traffic flow control of data trafficacross said first and second access technology layer ACC1, ACC2.

According to an embodiment of the present invention, a block 510determines a target service quality tSQ for data entity DE2. The targettSQ is for example a maximum congestion level of 3. The block 500determines the channel selection to b) as SQ1 reveals congestion levelof 6 and SQ2 reveals a congestion level of 2. The block 500 thereforedetermines the adhoc channel to transmit the data entity DE2 independence on the SQ1, SQ2 and tSQ.

The propagation range of data indicates an area, in which the datatransmitted by the road-side network node will be received by othernetwork nodes. The propagation range therefore also provides a secondarea, in which the data transmitted by the road-side network node willprobably not be received by other network nodes.

A block 502 determines and provides a target propagation range tPR forthe data of data entity DE1. A block 504 determines a first propagationrange PR1 via the sidelink radio channel of, e.g., 1.5 km. A block 506determines a second propagation range PR2 via the adhoc radio channelof, e.g., 1 km. The block 500 determines the channel selection CS to a)or b) in dependence on the target propagation range and in dependence onthe first and second message propagation range. As the targetpropagation range tPR is, e.g., 2 km, the sidelink radio channel isselected exclusively for the transmission of the data of data entityDE1. In an example not shown, the target propagation range is, e.g., 0.5km and the adhoc radio channel is selected exclusively for thetransmission of data.

If the block 500 determines a high congestion of one of the sidelinkradio channel and the adhoc radio channel. The block 500 overrides thedetermination of the channel selection CS in dependence on the targetpropagation if the high congestion is determined.

In an embodiment of the present invention, the block 500 determines thetransmission instruction to alternate a transmission initiation on thesidelink radio channel and the adhoc radio channel.

In an embodiment of the present invention, the block 500 determines thefirst repetition rate RR1 for the sidelink channel and the secondrepetition rate RR2 for the adhoc channel in dependence on the targetrepetition rate tRP, which is determined and provided by a block 508.For example if the target repetition rate tRR is 10 Hz, the first andsecond repetition rates RR1, RR2 are determined to 5 Hz.

According to an embodiment of the present invention, a number ofroad-side network nodes in the vicinity are determined. The block 500reduces the repetition rate RR1, RR2 of the transmission instructionsaccording to a) or b) if the determined number of road-side networknodes reaches a threshold in order to reduce traffic in the networks.

A block 512 determines a third repetition rate RR3 of data entitiesoriginating from at least one further road-side network node of thecell-supported radio communications network. The block 500 determinesthe first repetition rate RR1 in dependence on the third repetition rateRR3. For example, if a decreasing third repetition rate RR3 is sensed,the first repetition rate RR1 can be reduced as there are only fewvehicles in the vicinity. The third repetition rate RR3 is a mean valueand serves as a measure of channel congestion.

A block 514 determines a fourth repetition rate RR4 of data entitiesorigination from at least one further road-side network node of theadhoc radio communications network. The block 500 determines the secondrepetition rate RR2 in dependence on the fourth repetition rate RR4. Forexample, if a decreasing fourth repetition rate RR4 is sensed, thesecond repetition rate RR2 can be reduced as there are only few vehiclesin the vicinity. The fourth repetition rate RR4 is a mean value andserves as a measure of channel congestion. Preferably, each receiveddata entity is assigned to a specific known vehicle/network node in thevicinity of the receiving network node, e.g., by anonymizedvehicle/network node IDs. When measurements show that there is nonetwork node with a certain technology in communication reach of thesending network node, sending of data on this technology could beskipped or reduced until new vehicles appear.

According to an embodiment of the present invention, a block 516 providea transmission instruction request Tlr which originates by a facilitylayer function or an application layer function. The block 500determines the transmission instruction solely in dependence on thetransmission instruction request Tlr, if the transmission instructionrequest Tlr is provided. Therefore, the transmission instruction requestTlr overrides every other function which determines the transmissioninstruction.

FIG. 6 depicts schematically a flow chart to operate one of the networknodes NN5, NN6 of FIG. 1. In a Step 602 a similarity value is determinedin dependence on a first data entity to be transmitted and second dataentity, which has been transmitted. The similarity value reflects asimilarity and therefore also a difference between both data entities. Atransmission of the first data entity is initiated in step 604 if thesimilarity value exceeds a threshold. The similarity value is determinedaccording to FIG. 9 or 10, for example. The threshold is provided todistinguish between a sufficient difference between the first and seconddata entities in order to justify a data transmission.

FIG. 7 depicts schematically a flow chart for operating one of thenetwork nodes NN5, NN6 of FIG. 1. According to a step 702 data isreceived via the sidelink channel and/or the adhoc channel. According toa step 704 a danger level is determined in dependence on received data.According step 706 a minimum repetition rate is determined for at leastone of the sidelink radio channel and the adhoc radio channel independence on the danger level. The repetition rate is maintained in astep 708 for at least one of the sidelink radio channel and the adhocradio channel at or above the minimum repetition rate.

According to an embodiment of the present invention, the minimumrepetition rate for the sidelink channel is determined according to apre-configured or received proportion of network nodes capable of usingthe sidelink radio channel. According to an embodiment of the presentinvention, the minimum repetition rate for the adhoc channel isdetermined according to a pre-configured or received proportion ofnetwork nodes capable of using the adhoc radio channel.

According to an embodiment of the present invention, the received datacomprises a current speed and/or a current location of a distantvehicle. The danger level is determined in step 704 in dependence on thecurrent speed and current location.

FIG. 8 depicts schematically a flow chart to operate one of the networknodes NN5 and NN6 of FIG. 1. According to a step 802 a plurality offirst data entities are received via a sidelink radio channel of thecell-supported radio communications network. A plurality of second dataentities are received in step 804 via an adhoc radio channel of theadhoc radio communications network. According to a step 806 a similarityvalue is determined for at least a pair of data entities from theplurality of first and second data entities. According to a step 808 thepair of data entities is provided in dependence on the similarity value.The similarity value reflects a similarity and therefore reflects also adifference between the pairwise compared data entities.

FIG. 9 depicts schematically a reception coordination function which isoperated in one of the network nodes NN5, NN6 of FIG. 1. Data entitiesDE4, DE5 and DE6 are received via the adhoc channel ADHC. The dataentity DE5 is also received via the sidelink channel SLCH. All receiveddata entities DE3 to DE6 and the duplicate of DE5 are applied to a block902. The block 902 determines a similarity value SV for each pair of thedata entities DE4 to DE6 and the duplicate of DE5. A block 904 performsa threshold operation comparing the similarity value SV with at leastone of the threshold values Th1 and Th2. The first threshold value Th1is used for a threshold operation which determines whether to providethe respective data entity to a higher layerfunction.

A first data entity DE5 is received via the sidelink radio channel. Asecond data DE6 entity is received via the adhoc radio channel. Theblock 902 determines the similarity value SV in dependence on the firstand second data entities DE5, DE6. The first and second data entity DE5,DE5 are provided in dependence on the similarity value. For example, theduplicate DE5 on the radio channels is determined by blocks 902 and 904and only one instance of the data entity DE5 is provided to anapplication block 908. In yet another example, the blocks 902 and 904determine no similar data entity for the data entity DE6, thereforeproviding the data entity 6 to a facility layerfunction 910. Therefore,data aggregation is performed across the first and second accesstechnology layer ACCT, ACC2.

So, the data of data entity DE4 is received via the adhoc radio channelADCH. An exchange criterion EC indicating whether the received data hasto be injected into the adhoc radio channel or the sidelink channel isdetermined by block 904. The exchange criterion EC is determined if dataentity DE4 has no similar partner in a pair, which is determined by thethreshold operation using the threshold Th2 and if the data entity DE4has a destination address other than that of the network node. A block904 transmits the data entity DE4 via the sidelink radio channel independence on the exchange criterion.

According to an embodiment of the present invention, the block 904determines a high degree of similarity of two data entities, which arereceived in a subsequent order. The high degree of similarity indicatesthat the underlying data have undergone no change. So the provision ofboth of the data entities is rejected, if the similarity value indicatesthe high degree of similarity.

According to an embodiment of the present invention, the block 904selects the more recently received one of a pair of data entities, ifthe similarity value indicates a low degree of similarity, thereforeindicating a change in data or that both data entities are completelydifferent. Then, the block 904 provides the selected one of the dataentities.

According to an embodiment of the present invention, both data entitiesare provided, if the similarity value indicates a low degree ofsimilarity.

FIG. 10 depicts schematically a determination of the similarity valueSV. According to a step 1002, a weighted sum is initialized to Zero.According to a step 1004 parameters with identical type are searched forin the pair of data entities. If identical parameters exist, a step 1006will proceed to a step 1008. The step 1008 provides a comparison ofpayloads of the same type, for example payload B and payload E. A step1009 provides a comparison of the payloads of the same type which can bea correlation. The determined correlation value is multiplied with acorresponding weight. In a step 1010 the weighted difference which isthe result of step 1009 is added to the weighted sum. If no furtheridentical parameters exist for the pair of data entities, the weighteddifferences are scaled or standardized in step 1012. A step 1014 sums upthe weighted differences to the similarity value SV.

FIG. 11 depicts schematically a flow chart to operate one of the networknodes NN5, NN6. A list comprising further road-side network nodes in thevicinity of the road-side network node is determined according to a step1102. A node-individual plurality of data entities from the plurality offirst and second data entities which originate from one of the furtherroad-side network nodes of the list is determined in a step 1104. Thesimilarity value for at least a pair of data entities from thenode-individual plurality of data entities is determined according to astep 1106.

FIG. 12 depicts schematically a flow chart to operate one of the networknodes NN5, NN6 of FIG. 1. A step 1202 provides a discovering of at leastone further road-side network node in the vicinity of the road-sidenetwork node as a gateway node, wherein the at least one furtherroad-side node has the capability to exchange data across thecell-supported radio communications network and the adhoc radiocommunications network. A step 1204 provides an exchange of data acrossthe cell-supported radio communications network and the adhoc radiocommunications network in dependence on the discovered at least onefurther road-side network node.

FIG. 13 depicts schematically two interacting road-side network nodesNN5 and NN6 of FIG. 1. The network node NN6 transmits a data entity DE7via the adhoc radio channel and transmits a data entity DE8 via both thesidelink radio channel and the adhoc radio channel.

The network node NN5 receives the data entity DE8 from the furtherroad-side network node NN6 via the sidelink channel and receive the dataentity DE8 as a further data entity from the further road-side networknode NN6 via the adhoc channel. The block 902 determined the similarityvalue in dependence on the first and second data entity in this casebeing the duplicate of DE8. The block 904 discovers that the at leastone further road-side network node NN6 is a gateway node when thesimilarity value is above the threshold Th2.

The data entities may differ only in small time information given asinformation in the transmitted data. The data entities are similar whenthey have the same temporary identifier. The data entities are similarwhen they differ in small position information. The data entities aresimilar if an event indicated in a DENM message is identical andconsidered quite unlikely like a vehicle breakdown message.

As the data entity DE7 is received via the adhoc radio channel, thenetwork node NN5 transmits the data entity on the sidelink radio channeland thus transfers the data entity DE7 from one technology to the otherand in this way increases the reach of the data to potentially morevehicles.

FIG. 14 depicts schematically two interacting road-side network nodesNN5 and NN6 of FIG. 1. The further network node NN6 determines andtransmits a data entity DE14 via the adhoc channel. The network node NN5receives the data entity DE14 via the adhoc channel.

The network node NN6 inserts a first indication into the data entityDE14, which indicates that the network node NN6 is a gateway node. Thenetwork node NN5 receives the first indication and will insert thenetwork node NN6 into a list of gateway nodes in the vicinity of networknode NN5. The first indication may be transported as a bit i1 in acontrol section of data entity DE14.

According to an embodiment of the present invention, the data entityDE14 is of a gateway announcement message type. In another embodimentthe first indication is transported via another message type.

According to an embodiment of the present invention, the firstindication is a gateway address al.

The first indication that the transmitting road-side network node NN6 isa gateway node is signed by a hash to make it security proof. The hashis derived from a security certificate which is available only togateway nodes. Therefore no fake gateways will appear in the networksetup. Therefore, each gateway checks whether the indication istransmitted with a matching hash to increase security.

The data entity DE14 comprises a second indication i2 that thetransmitting road-side network node has transmitted the contents of thethird data entity on the sidelink radio channel and the adhoc radiochannel. In the shown example, the network node NN6 has not transmittedthe data entity DEM on the sidelink channel. Therefore, network node NN5knows from the second indication set to Zero or false that an adhoc-onlytransmission has occurred on the side of network node NN6. In order totransfer the data entity DEM into the other network, the network nodeNN5 transmits via block M02 the contents of the data entity DEM only viathe sidelink channel when the third data has been received via the adhocchannel and the second indication is not true.

On the other hand, the network node NN5 will transmit the contents of adata entity only via the adhoc channel when the third data has beenreceived via the sidelink channel and the second indication is not true.

A block M04 determines a number of further road-side network nodesoperating as a gateway in the vicinity of network node NN5. Block M02exchanges data across the cell-supported radio communications networkand the adhoc radio communications network in inverse proportion to thenumber of further road-side network nodes operating as a gateway.

The invention claimed is:
 1. A road-side network node, comprising: aprocessor; a memory; a first radio module configured to operate in acell-supported radio communications network; a second radio moduleconfigured to operate in an adhoc radio communications network; and atleast one antenna; wherein the road-side network node is configured to:provide data to be transmitted; determine a transmission instruction forthe data, the transmission instruction including a channel selectionindicating: a) a transmission of the data via a sidelink radio channelof the cell-supported radio communications network, or b) a transmissionof the data via an adhoc radio channel of the adhoc radio communicationsnetwork, or c) a transmission of the data via the sidelink radio channeland the adhoc radio channel; and initiate a transmission of the data viathe sidelink radio channel and/or via the adhoc radio channel accordingto the transmission instruction, wherein the road-side network node isconfigured to: determine a first Service quality of the sidelink radiochannel; determine a second Service quality of the adhoc radio channel;determine the channel selection in dependence on the first Servicequality and the second Service quality, wherein the road-side networknode is configured to: determine a first repetition rate of thetransmission instruction in dependence on the first Service quality andthe second Service quality; determine a second repetition rate of thetransmission instruction in dependence on the first Service quality andthe second Service quality; reiteratively initiate the transmission ofthe data via the sidelink radio channel according to the firstrepetition rate; and reiteratively initiate the transmission of the datavia the adhoc radio channel according to the second repetition rate. 2.The road-side network node according to claim 1, wherein the road-sidenetwork node is configured to: determine the radio channel with a highercongestion value in dependence on the first and second Service quality;and decrease the first repetition rate for the sidelink radio channelwhen the sidelink radio channel has the higher congestion value anddecrease the second repetition rate for the adhoc radio channel when theadhoc radio channel has the higher congestion value.
 3. The road-sidenetwork node according to claim 1, wherein the road-side network node isconfigured to: determine the first repetition rate for the sidelinkchannel and the second repetition rate for the sidelink channel independence on a target repetition rate.
 4. The road-side network nodeaccording to claim 1, wherein the road-side network node is configuredto: determine or provide a target propagation range for the data;determine a first propagation range via the sidelink radio channel;determine a second propagation range via the adhoc radio channel;determine the channel selection to a) or b) in dependence on the targetpropagation range and in dependence on the first propagation range andthe second propagation range.
 5. The road-side network node according toclaim 4, wherein the road-side network node is configured to: determinea high congestion of one of the sidelink radio channel and the adhocradio channel; and override the determination of the channel selectionin dependence on the target propagation based on the determination ofthe high congestion.
 6. The road-side network node according to claim 1,wherein the road-side network node is configured to: determine thetransmission instruction to alternate a transmission initiation on thesidelink radio channel and the adhoc radio channel.
 7. The road-sidenetwork node according to claim 1, wherein the road-side network node isconfigured to: determine a similarity value in dependence on a firstdata entity to be transmitted and second data entity, which has beentransmitted; and initiate a transmission of the first data entity if thesimilarity value exceeds a threshold.
 8. The road-side network nodeaccording to claim 1, wherein the road-side network node is configuredto: receive data via the sidelink channel and/or the adhoc channel;determine a danger level in dependence on received data; determine aminimum repetition rate for at least one of the sidelink radio channeland the adhoc radio channel in dependence on the danger level; andmaintain a repetition rate for at least one of the sidelink radiochannel and the adhoc radio channel at or above the minimum repetitionrate.
 9. The road-side network node according to claim 8, wherein thereceived data includes a current speed of a distant vehicle and/or acurrent location of the distant vehicle, the road-side network nodebeing configured to: determine the danger level in dependence on thecurrent speed and current location.
 10. The road-side network nodeaccording to claim 1, wherein the road-side network node is configuredto: provide a transmission instruction request by a facility layerfunction or an application layer function; and determine thetransmission instruction solely in dependence on the transmissioninstruction request, when the transmission instruction request isprovided.
 11. A road-side network node, comprising: a processor; amemory; a first radio module configured to operate in a cell-supportedradio communications network; a second radio module configured tooperate in an adhoc radio communications network; and at least oneantenna; wherein the road-side network node is configured to: providedata to be transmitted; determine a transmission instruction for thedata, the transmission instruction including a channel selectionindicating: a) a transmission of the data via a sidelink radio channelof the cell-supported radio communications network, or b) a transmissionof the data via an adhoc radio channel of the adhoc radio communicationsnetwork, or c) a transmission of the data via the sidelink radio channeland the adhoc radio channel; and initiate a transmission of the data viathe sidelink radio channel and/or via the adhoc radio channel accordingto the transmission instruction, wherein the road-side network node isconfigured to: determine a first repetition rate of the transmissioninstruction in dependence on the first Service quality and the secondService quality; determine a second repetition rate of the transmissioninstruction in dependence on the first Service quality and the secondService quality; reiteratively initiate the transmission of the data viathe sidelink radio channel according to the first repetition rate; andreiteratively initiate the transmission of the data via the adhoc radiochannel according to the second repetition rate, wherein the road-sidenetwork node is configured to: determine a third repetition rate of atleast one further road-side network node of the cell-supported radiocommunications network; and determine the first repetition rate independence on the third repetition rate.
 12. The road-side network nodeaccording to claim 11, wherein the road-side network node is configuredto: determine a fourth repetition rate of at least one even furtherroad-side network node of the adhoc radio communications network; anddetermine the second repetition rate in dependence on the fourthrepetition rate.
 13. A method to operate a road-side network node in acell-supported radio communications network and in an adhoc radiocommunications network, the method comprising the following steps:providing data to be transmitted; determining a transmission instructionfor the data, the transmission instruction including a channel selectionindicating a) a transmission of the data via a sidelink radio channel ofthe cell-supported radio communications network, or b) a transmission ofthe data via an adhoc radio channel of the adhoc radio communicationsnetwork, or c) a transmission of the data via the sidelink radio channeland the adhoc radio channel; and initiating a transmission of the datavia the sidelink radio channel and/or via the adhoc radio channelaccording to the transmission instruction, wherein the road-side networknode is configured to: determine a first Service quality of the sidelinkradio channel; determine a second Service quality of the adhoc radiochannel; determine the channel selection in dependence on the firstService quality and the second Service quality, wherein the road-sidenetwork node is configured to: determine a first repetition rate of thetransmission instruction in dependence on the first Service quality andthe second Service quality; determine a second repetition rate of thetransmission instruction in dependence on the first Service quality andthe second Service quality; reiteratively initiate the transmission ofthe data via the sidelink radio channel according to the firstrepetition rate; and reiteratively initiate the transmission of the datavia the adhoc radio channel according to the second repetition rate.